This double-blind, randomised, controlled study compared the efficacy of candesartan cilexetil 8 mg (n = 87) and losartan 50 mg (n = 89), once daily for 6 weeks, relative to placebo (n = 80) in patients with mild-to-moderate essential hypertension (diastolic blood pressure (DBP): 95-115 mmHg). Ambulatory BP measurements were done every 15 min over 36 h. At the end of the 6-week treatment, the mean change in DBP between the baseline and the 0-24-h period after the last dose of study medication was greater in patients receiving candesartan cilexetil 8 mg (-7.3 mmHg +/- 6.9 mmHg) compared with losartan 50 mg (-5.1 mmHg +/- 4.9 mmHg) (p < 0.05) or placebo (0.3 mmHg +/- 6.5 mmHg) (p < 0.001). The mean change in systolic BP (SBP) during this time was greater in patients receiving candesartan cilexetil 8 mg (-10.8 mmHg +/- 11.3 mmHg), or losartan 50 mg (-8.8 mmHg +/- 8.9 mmHg) than placebo (1.2 mmHg +/- 9.9 mmHg) (p < 0.001). Candesartan cilexetil 8 mg was associated with a greater reduction in DBP and SBP, relative to placebo, when compared with losartan 50 mg, during both daytime and night-time, and between 12 and 24 h after dosing (p < 0.001). Both active treatments were well tolerated. In patients with mild-to-moderate essential hypertension, candesartan cilexetil 8 mg therefore had greater, more consistent antihypertensive efficacy throughout the day and the night, and long-lasting efficacy after the last dose, compared with losartan 50 mg. This greater efficacy is maintained with an excellent tolerability associated with members of the angiotensin Il type 1-receptor blocker class.